* Command "cdreload" registered to Main class

* Now project is buildable on GitHub
* Back to Sync from Async. Because some countdown bugs.
* Now half-seconds can be configurable (Cooldown: 1 = 0.5 second)
* HashSet is now used instead of ArrayList

" Delayed task" code changed from Sync to Async. The delay doesn't use server's main thread anymore.

Removed isOp() check and add permission as default op to plugin.yml. Bypass permission is " chatcooldown.bypass"

Changed Cooldown Timer code from global time to unique time for each player.

Thank you @Benliam12